Method of and apparatus for forming sheet glass



Nov. 30 1.926.

1,608.644 H. M. BLACK METHOD OF AND APPARATUS FOR FORMING SHEET GLASSFiled March 1. 1926 3 Sheets-Sheet 1 FIG.1

llLLL INVENTOR HAROLD M. BLACK Nov. 30 1926 1,608,644 7 H. M. BLACKMETHOD OF AND APPARATUS FOR FORMING SHEET GLASS Filed March 1, 1926 3Sheets-Sheet 2 FIG. 3

INVENTOR HARqLa M. BLACK Nov. 30 1926.

V H. M. BLACK METHOD OF AND APPARATUS FOR FORMING SHEET GLASS FiledMarch 1. 1926 3 Shets-Sheet 5 lNV HAROLD BLAC Patented Nov. 30, 1926;

marten STATES PATENT OFFICE.

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/ METHOD OF AND .AIPPAR A'ZH'J'S F01; FORM ING SH EET GLASS,-

Application filed March 1, 1926. seriai No. 91,355.

My invention relates to a method and 'apparatus for forming sheet glass,and particularly to the rolling of plate glass by a continuous process.

One of the methods heretofore employed for manufacturing plate glassconslsts in flowing a stream of glass from a spout upon a receivingroll-and against a sheet-forming roll, the spout beinglrelatively narrowas compared to the finished sheet, so as to secure a stream of suchdepth as will avoid waves and overlaps and excessive cooling of theglass before reaching the receiving roll. This relatively narrow, deep,stream has been directed against the breast of a' sheet-forming roll andcaused to flow laterally to form a sheet of the desired width. However,those portions of the mass of glass which are deflected laterally becomechilled through contact with the roll or otherwise,

causing ream or other defects in the finished I sheet.

My invention has for its object the provision of means whereby moltenglass can be more efl'ectiv'elyspread to form a sheet ground andpolished.

Another objectof my invention is to provide a means for forming glasssheets wherein ream and other irregularities are reduced to a minimum.

Some of the ways by which my invention may be practiced are shown in the,accoms panying drawing, wherein Fig. 1 is a sectional view showing aportion of a glass furnace and sheet-forming mechanism mounted inconjunction therewith: Fig. 2 is a plan view of the apparatus of Fig. 1;Fig. 3 is of Fig. 1, looking toward thedischarge end of the spout; Fig.4 is a transverse sectional view of the initial sheet of glass, thesection being taken forwardly of the sheet-forming 1 rolls of Fig. 1;Fig. 5 is a view showing the manner in which a mass of molten. glass.will 1 spread if placed upon ,a sphericalrsurface; Figs. 6 and 7 areviews showingthe spreading action of the glass when placed upon acylindrical-surface;" Fig. 8 is a view similar a n F I show a portion ofa glassfurproyided with a spout ing chilled.

a transverse sectional view of the apparatus to Fig. ,1, but showing amodified forln of apparatus,'and Fig. 9is a planview showin ,a portionofl the apparatus of Fig. 8.

12 and a gate 13 for controlling the flow of glass to the spout.

At the forward end of 'thespout' a roll 14 is provided which serves as atable upon which the glass discharged from the spout 12 is rolled tosheet form by a roller 15. A

brush roll 16 is provided for cleaning the surface of the roll 14. Therollers 14, 15

and 16 may be driven from any suitable source of power (not shown). Theperipheral surface of the roll 14 is of convex form as indicatedby thelines 14 and 14" of Fig.2. The roll 15 is of'concave form, as shown moreclearly in Fig. 2, with its ia spherical surface 19, as shown in Fig. 5,of glass which will be of high quality when? cylindrical surface has asharp enough curvature, the mass of glass may assume the. shape shown at20 in Figf? before beco Therefore, it is possible to eifectsubstantially any desired rate of spreading flow of the glassupontheroll 14 in order to provide suflicient glass at, the ends of theroll 14 to form a sheet whose edges have-the dcsired thickness.

In Fig. 2 I have indicated approximately 'the directions in whichparticles ofv glass a,

b, and 0- will flow. In, ordinary practice,

-particles at a and 0 would follow j paths indicatedzby the dottedlines, since they would first be, brought against the mid portion oftable or roll 14 be curved, however, the glass from a and 0 will followapproxiinc theroll and then deflected laterally. If the Y will completetheir travel in substantially Y the same the parti particles at thepoints a, b and occupy the same general relative positions in thecompleted sheet occupied by-them in the stream of glass, thus'reducingrelativedisplacementot the particles of. molten glass, and consequentlythe tendency toward the formation. of ream in the sheet.-

If the receiving roll 14 (Fig. 1) had a cylindrical surface, the glasswould build up in a mass'against' the roll 15 and with,-a

T considerable depth at the center, forming a contour A which would tendto chill and mix and roll into the hotterglass, causing ream. Owing tothe lateral spreading caused by the lateral gravity flow on the"convexre ceiving roller, instead of contour'A we'have one more like Bat thecenter of the roll Y15 and 0 near the endpf roll 15. and butslight-building, up against the roll. Also,.

'ls's glass would-.be in storage between the roll 15 and spout 12, andthis would mean.

less difference in time of-transit of one particle relative to anotherand would therefore cause the glass .to pass under the roll at amoreeven'laverage temperature.

The glass deposited upon the roll 14 s spread bythe roller 15 to form asheet "22' which is convex in cross section as indicated in Figs. 1 and4. The sheet while still hot is then passed between the flattening rolls23' and 24. The flattening of the sheet causes it to assume the formshown in Fig. 4 by dotted lines 22.

In Fig. 8 I have shown rollers 25 and-26 that correspond to the rollers14 and 15, of

tened form bv its own weight,

.Fig. '1, and which form a sheet 27 .of con-.

vex form. However, instead of passing the sheet 27through flatteningrolls as in Fig. 1, it is directed to a table 28 which. is ofconvex-form at its glass receiving end. and

gradually changes to flat form toward its d scharge end. The sheet 27may be of such temperature that it will follow the contour of thesurface of the table 28 and thereafter settle to fiat form without the oemployment of flattening rolls.

In case.the,sheet 27 is advanced too rap,

- idly to permitrit to settle to the surface of the table 28. or is toocool to assume a flat- Iprdvide a flattening roll 29 that is secured ateach end to a spring 30 that is in turn connected to an eye bolt; 31 whch has screw, threaded engagement with an. adjusting nut 32. LEach ofthe nuts 32 is carried in a bracket 33 secured to the'table 28. Byrotating the nut 32 the pressure exerted. upon the sheet on glass by theroll 29 may be controlled and thesheet'may be advanced by--feed rollersof any suitable form, one of which is indicated at 34, and fed intoa-leer for treatment in the usual manner.

While ,,I have shown and described my invention as appl ed to theformation of glass sheets, it will be apparent that the method andapparatus maybe employed in 9 the formation of sheets or slabs ofvarious other kinds of plastic materials.

I claim as my invention:

1. The method of forming sheet glass, which comprises, depositing astream of molten glass upon a moving table having a convex surface.

2. The method of. forming sheet glass, which comprises depositing ,astream of molten glass upon a moving table having a convex surface, andreducing the thickness of the glass while on said table, by asheetformi'ng member of concave form.

3. The method of forming sheet glass which consists in depositing astream of molten glass upon the mid portion of a roll molten glass uponthe mid portion of a roll of convex form, and moving said roll beneath aconcave surface to effect spreading of the glass.

5. The method which comprises depositing molten glass upon a convexsurface while imparting relative movementtosaid surface and said glassin a substantially horizontal plane, and flattening said glass after itbecomes partially set.

6. The method which comprises depositing molten glass upon a convexsurface while imparting relative movement to said surface and said glassin a substantially horizontal plane.

7. Apparatus for forming sheet glass comprising a roll of convex form,means for depositing molten glass upon the mid portion of said roll, anda concave roll 00- operating with the first-named roll to eflect uniformdistribution of the glass in the form of a sheet.

'8. Sheet glass formingapparatus compnidsing a movable member of convexform,-- an glass to approximately the mid portion of said member. I

9. Sheet-glass forming apparatus comprising a movable member of convexform,

means for directing a flow of molten glass form a sheet-of the desiredthickness. v I

,Sheet glass forming apparatus comprising a movable member of convexform,

means for directing a flowozf molten approixrmately the mid portion ofsaid,

means for. directing a flow of molten member, and means for flatteningsaid glass when it.becomes partially set.

longitudinal axis of the stream, independently of the action of saidroll, and thereafter passing the glass under said roll.

12. The method of forming sheet glass, which comprises directing astream of molten glass to a receiving surface in advance of asheet-forming roll, causing said glass to flow in a direction diagonalto the longitudinal axis of'the stream, independently of the action ofsaid roll, and thereafter passing the glass in a forward direction undersaid roll.

13. The method of. forming sheet glass, which comprises directing astream of molten glass of relatively great thickness toward asheet-forming roll, and causing said stream to spread to a depth notgreately in excess of the finished sheet of glass, imme diatelypreceding contact with the roll.

14. The method of forming she'et glass, which consists in flowing astream of glass toward a sheet-forming roll, causing said stream tospread laterally beforecontac'ting with the roll, and advancing allspread portions'of the stream at substantially a uniform rate of speed.7 a

15. The method of forming sheet glass, which comprises rolling a moltenmass of glass to a sheet that is curved in cross section, and flatteningsaid sheet wh-ile still plastic. I

16. The method of making sheet glass, which comprises forming a. sheetof the desired thickness, and thereafter increasing the width of saidsheet.

17.. The method of forming sheet glass, which comprises depositing amass of molten glass upon a convex surface, and rolling said mass whileon said surface.

'18. The method of forming sheet glass,

which eomprises rolling a mass of molten glass into a sheet that ispartially cylindrical in cross section, flattening. the sheet whilestill plastic, and

the same.

19, The method of forming sheet glass,

which comprises rolling a mass of molten thereafter annealing glass intoa sheet that is partially cylindrical in cross section, and flatteningthe sheet while being moved-from rolling position to annealing position.

Signed at Butler, Pa, this 25th day of February, 1926.

' HAROLD M. BLACK.

